The present invention relates to a lower vehicle body structure of a vehicle, in which a floor panel is provided between a pair of side sills extending longitudinally, a tunnel portion extending longitudinally is provided at a central portion of the floor panel, and a seat for a passenger is provided between the side sill and the tunnel portion.
Conventionally, the structures disclosed in Japanese Laid-Open Publication Nos. 2005-247003 and 2000-203449 are known as the above-described lower vehicle body structure.
In these structures disclosed in the above publications, a pair of side sills extending longitudinally is provided, a floor panel is provided between these side sills, a tunnel portion extending longitudinally is provided at a central portion of the floor panel, a plurality of cross members extending in a vehicle width direction are provided on the floor panel with a specified distance therebetween longitudinally so as to interconnect the side sill and the tunnel portion, and a pair of seat rails is provided between front and rear cross members so as to guide a seat for a passenger longitudinally.
These conventional structures have a problem in that a rigidity of the vehicle body would not be sufficient against a vehicle side crash. Further, in the vehicle body structures disclosed in the above publications, which have a centre pillar, a so-called belt-in seat (a type of seat equipped with a retractor to wind up a seatbelt therein) may be generally applied in a case where a center-pillar-less vehicle body is adopted for providing passengers with easy ingress and egress. Herein, the structure in which loads applied to the seat and seatbelt are configured to be transmitted to the cross members has a problem in that the cross members would be deformed improperly at the vehicle crash.
Meanwhile, another type of lower vehicle body structure of a vehicle shown in FIG. 16 is also known. Namely, this is a structure, as shown in the figure, in which a pair of side sills 100, 100 extending longitudinally are provided, a floor panel 101 is provided substantially horizontally between the side sills 100, 100, a tunnel portion 102 is provided at a central portion of the floor panel 101 so as to project toward the inside of the vehicle and extend longitudinally.
Further, there are provided pocket lower rails 103, 103 inside the side sills 100, 100 so as to extend longitudinally and partially, cross members 104, 104 are provided at a front portion on the floor panel 101 so as to respectively interconnect the side sill 100 and the tunnel portion 102 in the vehicle width direction, and cross members 105, 105 are provided at a rear portion on the floor panel 101 so as to respectively interconnect the pocket lower rail 103 and the tunnel potion 102 in the vehicle width direction.
Also, between the cross members 104, 105 is provided a pair of seat rails 106, 106 to guide a seat for a passenger longitudinally.
The structure shown in FIG. 16 may have a more increased vehicle body rigidity because of the pocket lower rails 103, compared with the structures disclosed in the above patent publications. However, the rigidity would not be sufficient yet against the vehicle side crash or the like.
Also, since the pair of seat rails 106, 106 interconnects the front and rear cross members 104, 105, there is still a problem in that the cross members would be improperly deformed at the vehicle crash or the like in a case where the vehicle is the so-called center pillar-less one equipped with the belt-in seat.